Amana neither fridge nor freezer getting cold... I bought a used Amana bottom freezer

Question

I bought a used Amana bottom freezer refrigerator a month ago, and just starting today the freezer is not getting cold enough to freeze, and the fridge is not getting cold enough to keep the milk from spoiling. Although the fan is running, it's not getting cold enough, even when I put it to the highest setting possible.The two things I've noticed is that fan is blowing room temperature air out of the back of the fridge, and there is A LOT of frost on the back of the freezer wall. I don't know if these are two good or bad things (since I know little about fridges)